How To Setup Kubernetes Cluster Using Kubeadm

 

What is Kubeadm?

Kubeadm is a tool to set up a minimum viable Kubernetes cluster without much complex configuration. Also, Kubeadm makes the whole process easy by running a series of prechecks to ensure that the server has all the essential components and configs to run Kubernetes.

It is developed and maintained by the official Kubernetes community. There are other options like minikube, kind, etc., that are pretty easy to set up.

• Install docker fallow the link check for different flavours 

       

Platform	x86_64 / amd64	arm64 / aarch64	arm (32-bit)	s390x
CentOS
Debian
Fedora
Raspbian
RHEL
SLES
Ubuntu
Binaries

• Install kubelet kubeadm kubectl 

Debian Family 

1. Update the apt package index and install packages needed to use the Kubernetes apt repository:

   sudo apt-get update
   sudo apt-get install -y apt-transport-https ca-certificates curl
   

2. Download the Google Cloud public signing key:

   sudo curl -fsSLo /usr/share/keyrings/kubernetes-archive-keyring.gpg https://packages.cloud.google.com/apt/doc/apt-key.gpg
   

3. Add the Kubernetes apt repository:

   echo "deb [signed-by=/usr/share/keyrings/kubernetes-archive-keyring.gpg] https://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee /etc/apt/sources.list.d/kubernetes.list
   

4. Update apt package index, install kubelet, kubeadm and kubectl, and pin their version:

   sudo apt-get update
   sudo apt-get install -y kubelet kubeadm kubectl
   sudo apt-mark hold kubelet kubeadm kubectl

Redhat Family (Redhat,Centos,AWS linux ...)

cat <<EOF | sudo tee /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-\$basearch
enabled=1
gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
exclude=kubelet kubeadm kubectl
EOF

# Set SELinux in permissive mode (effectively disabling it)
sudo setenforce 0
sudo sed -i 's/^SELINUX=enforcing$/SELINUX=permissive/' /etc/selinux/config

sudo yum install -y kubelet kubeadm kubectl --disableexcludes=kubernetes

sudo systemctl enable --now kubelet

On Master Node:

1. Initialize Kubernetes Cluster

   kubeadm init 

2. Create a user for kubernetes administration and copy kube config file.
   
   

     mkdir -p $HOME/.kube
     sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
     sudo chown $(id -u):$(id -g) $HOME/.kube/config

3. Deploy Calico network as a kubeadmin user.

   This should be executed as a user (heare as a kubeadmin )

   curl https://docs.projectcalico.org/manifests/calico-typha.yaml -o calico.yaml
   kubectl apply -f calico.yaml

4. Cluster join command

   kubeadm token create --print-join-command

On Worker Node:

1. Add worker nodes to cluster

   Use the output from kubeadm token create command in previous step from the master server and run here.

   look like this 

   kubeadm join 172.31.24.89:6443 ....

2. Verifying the cluster To Get Nodes status

   kubectl get nodes

   To Get component status

   kubectl get cs

Check The kubernets cluster using sample webapp

[root@ip-172-31-24-89 ec2-user]# kubectl create deployment nginx --image=gudditi/myresume

deployment.apps/nginx created

[root@ip-172-31-24-89 ec2-user]# kubectl expose deployment nginx --type=NodePort --port=80 --target-port=80 --name=nginxsvc

service/nginxsvc exposed

[root@ip-172-31-24-89 ec2-user]# kubectl get svc

NAME         TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)        AGE

kubernetes   ClusterIP   10.96.0.1      <none>        443/TCP        8m19s

nginxsvc     NodePort    10.96.88.173   <none>        80:32599/TCP   5s

browse application using

http://<master/workernode ipaddress>:<port>